U.S. patent application number 16/614013 was filed with the patent office on 2020-03-05 for tensioner for an accessory drive of a motor vehicle.
This patent application is currently assigned to DAYCO EUROPE S.R.L.. The applicant listed for this patent is DAYCO EUROPE S.R.L.. Invention is credited to Emanuele ANGELUCCI, Sabrina BERTAGGIA, Gianluca CARICCIA, Andrea MONTANI, Claudio UBERTIS ALBANO.
Application Number | 20200072323 16/614013 |
Document ID | / |
Family ID | 60020385 |
Filed Date | 2020-03-05 |
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United States Patent
Application |
20200072323 |
Kind Code |
A1 |
MONTANI; Andrea ; et
al. |
March 5, 2020 |
TENSIONER FOR AN ACCESSORY DRIVE OF A MOTOR VEHICLE
Abstract
Tensioner for an accessory drive of a motor vehicle each have a
support element adapted to be fixed on an electric machine, an
intermediate element carried by the support element and rotating
with respect thereto about a first fixed axis, a rigid tensioner
element rotating with respect to the intermediate element about a
second axis parallel to the first axis, a pair of tensioner pulleys
carried by the tensioner element and adapted to cooperate with
respective branches of an endless drive element of the drive
positioned on opposite sides with respect to the electric machine,
and a spring acting between the support element and the
intermediate element to push the tensioner pulleys into contact
with the endless drive element.
Inventors: |
MONTANI; Andrea; (Chieti,
IT) ; CARICCIA; Gianluca; (Chieti, IT) ;
ANGELUCCI; Emanuele; (Chieti, IT) ; BERTAGGIA;
Sabrina; (Chieti, IT) ; UBERTIS ALBANO; Claudio;
(Chieti, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAYCO EUROPE S.R.L. |
Chieti |
|
IT |
|
|
Assignee: |
DAYCO EUROPE S.R.L.
Chieti
IT
|
Family ID: |
60020385 |
Appl. No.: |
16/614013 |
Filed: |
May 17, 2018 |
PCT Filed: |
May 17, 2018 |
PCT NO: |
PCT/IB2018/053480 |
371 Date: |
November 15, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 2007/0865 20130101;
F16H 2007/0874 20130101; F16H 2007/0893 20130101; F16H 2007/081
20130101; F16H 7/12 20130101; F16H 7/08 20130101 |
International
Class: |
F16H 7/12 20060101
F16H007/12 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2017 |
IT |
102017000053588 |
Claims
1. A tensioner for an accessory drive of a motor vehicle provided
with an internal combustion engine and a reversible electric
machine acting as motor and generator, the drive comprising at
least a first pulley mounted on a drive shaft of the internal
combustion engine, a second pulley mounted on the shaft of the
electric machine and an endless drive element cooperating with at
least said first pulley and said second pulley, the tensioner
comprising: a support element fixedly mountable on or close to the
electric machine; an intermediate element carried by the support
element and rotating with respect thereto about a first fixed axis;
a rigid tensioner element rotating with respect to the intermediate
element about a second axis parallel to the first axis and distinct
therefrom; a first tensioning pulley and a second tensioning pulley
carried by the tensioner element and rotating with respect thereto
about respective axes distinct from said first axis and second axis
and arranged in use in a fixed relative position; and at least one
spring acting between the support element and the intermediate
element to push the first and second tensioning pulleys into
contact with respective branches of the endless drive element
positioned on opposite sides with respect to the second pulley.
2. The tensioner according to claim 1, wherein the support element
comprises an annular sleeve or a pin defining the first axis.
3. The tensioner according to claim 1, wherein the support element
comprises a plurality of fixing holes for the connection to a
casing of the electric machine.
4. The tensioner according to claim 1, wherein the intermediate
element comprises a hub portion rotatably mounted on the support
element about the first axis and an aim portion extending radially
from the hub portion and defining the second axis.
5. The tensioner according to claim 4, wherein the hub portion is
housed in a rotating manner about the sleeve or pin of the support
element.
6. The tensioner according to claim 1, wherein the intermediate
element comprises a first pin defining the second axis and the
tensioner element comprises a seat rotatably coupled to said first
pin.
7. The tensioner according to claim 6, said intermediate element
comprises a second pin for rotatably coupling with the support
element, said first and second pins extending on axially opposite
sides.
8. The tensioner according to claim 1, wherein said intermediate
element is disc-shaped.
9. The tensioner according to claim 1, wherein the tensioner
element has a closed annular shape.
10. The tensioner according to claim 1, wherein the tensioner
element comprises a hub portion constrained to said intermediate
element and two arms extending radially from the hub portion and
bearing the respective first and second tensioning pulleys.
11. The tensioner according to claim 10, comprising a stiffening
portion connecting the two arms to each other.
12. The tensioner according to claim 1, wherein the second
tensioning pulley is mounted in an adjustable manner on the
tensioner element to vary the installation tension of the endless
drive element.
13. The tensioner according to claim 12, wherein the tensioner
element comprises an intermediate support element for said second
tensioning pulley rotatably mounted about a third axis with respect
to the tensioner element and a blocking element for blocking the
intermediate support element on the tensioner element in a
selectable position to obtain a predetermined tension value of the
endless drive element.
14. The tensioner according to claim 13, wherein the blocking
element slidingly engages a first elongated slot of the tensioner
element extending along a circumference centered about said third
axis.
15. The tensioner according to claim 14, wherein said tensioner
element is formed by two half shells, identical to and superimposed
on each other, and said first tensioning pulleys is carried by a
support engaging a second elongated slot on said tensioner element
in a fixed manner.
Description
PRIORITY CLAIM
[0001] This application claims priority from Italian Patent
Application No. 017000053588 filed on 17 May 2017, the disclosure
of which is incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to a tensioner for an
accessory drive of a motor vehicle.
BACKGROUND ART
[0003] In motor vehicles, a reversible electric machine is
increasingly frequently used in place of the conventional
alternator; said electric machine can operate as a generator but
also as an electric motor at start-up or as a booster motor.
[0004] The accessory drive generally comprises a pulley connected
to the drive shaft and a pulley connected to the rotor of the
electric machine, and can comprise one or more pulleys for driving
other accessories, for example the conditioning system compressor.
The accessory drive further comprises a belt for transmission of
the movement between the above-mentioned pulleys and a tensioner
adapted to ensure a correct minimum tension level of the belt and
avoid slipping between the same and the pulleys.
[0005] In conventional accessory drives, in which the electric
machine is an alternator driven by the motor, the tensioner acts on
the slack branch of the belt, i.e. the branch positioned downstream
of the motor and upstream of the alternator with reference to the
direction of movement of the belt.
[0006] The use of a reversible electric machine means that the
branch, of the belt which is tensioned in the operating conditions
in which the electric machine is driven by the motor becomes the
slack branch when the torque is delivered by the electric
machine.
[0007] Various solutions that enable both branches of the belt to
be tensioned have therefore been developed.
[0008] One solution consists, for example, in using a tensioner
with two arms hinged in a shared pin and bearing respective
pulleys. The arms are subject to the elastic force of a spring
which tends to move them close to each other so as to keep the
pulleys in contact with respective branches of the belt. An example
of this solution is described for example in EP 1581753-A. The
shared axis of the two arms can be inside or outside the path of
the belt.
[0009] Another solution consists in mounting the tensioner on the
electric machine. According to this solution, the tensioner
comprises an annular element rotating about the axis of the
electric machine and bearing a pulley, and an arm articulated or
sliding in respect to the annular element and bearing the other
pulley; a spring is interposed between the annular element and the
arm so as to push the pulleys into contact with the belt.
[0010] The known solutions are not optimized in terms of reactivity
to sudden tension changes in the belt, in particular in the
transition steps between the different operating modes of the
electric machine.
DISCLOSURE OF INVENTION
[0011] One object of the invention is to solve the above-mentioned
problem. A further object of the present invention is to ensure
compensation of the belts elongation over time, without loss of
reactivity.
[0012] The above-mentioned objects are achieved by a tensioner
according to claim 1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a better understanding of the present invention three
embodiments are described, by way of non-limiting example and with
reference to the attached drawings, in which:
[0014] FIG. 1 is a schematic view of an accessory drive for a
vehicle comprising a tensioner according to the present
invention;
[0015] FIGS. 2, 3 and 4 are functional diagrams of three
embodiments of the present invention;
[0016] FIG. 5 is a front elevation view of a tensioner according to
the first embodiment of the invention;
[0017] FIG. 6 is a rear elevation view of the tensioner of FIG.
5;
[0018] FIG. 7 is a section according to line VII-VII of FIG. 6;
[0019] FIG. 8 is a section according to line VIII-VIII of FIG.
6;
[0020] FIGS. 9 and 10 are exploded perspective views, from opposite
sides, of the tensioner of FIGS. 5 and 6;
[0021] FIG. 11 is a front elevation view of the second embodiment
of the tensioner according to the invention;
[0022] FIG. 12 is a rear elevation view of the tensioner of FIG.
11;
[0023] FIG. 13 is a section according to line XIII-XIII of FIG.
11;
[0024] FIG. 14 is a section according to line XIV-XIV of FIG.
11;
[0025] FIGS. 15 and 16 are exploded perspective views, from
opposite sides, of the tensioner of FIGS. 11 and 12;
[0026] FIG. 17 is a front elevation view of a tensioner according
to the third embodiment of the invention;
[0027] FIG. 18 is a rear elevation view of the tensioner of FIG.
18;
[0028] FIG. 19 is a section according to line XIX-XIX of FIG.
18;
[0029] FIG. 20 is a section according to line XX-XX of FIG. 18;
[0030] FIGS. 21 and 22 are exploded perspective views, from
opposite sides, of the tensioner of FIGS. 17 and 18.
BEST MODE FOR CARRYING OUT THE INVENTION
[0031] With reference to FIG. 1, an accessory drive for a motor
vehicle is indicated overall by 1.
[0032] The drive 1 comprises a first pulley 2 rotationally coupled
to a drive shaft 3 of an internal combustion engine 4 of the
vehicle, a second pulley 5 rotationally coupled to a rotor of a
reversible electric machine 6 and a third pulley 7 for driving a
compressor (not illustrated) of a conditioning system of the
vehicle.
[0033] The transmission 1 further comprises an endless drive
element 9, preferably a poly-V belt, which cooperates with the
first, second and third pulley 2, 5, 7 for driving the movement
between these latter.
[0034] The drive 1 lastly comprises a tensioner 10 mounted on (or
close to) the electric machine 6 and comprising (FIGS. 2-4): [0035]
a support element 11 adapted to be fixed on or close to the
electric machine, inside or outside the path of the belt, [0036] an
intermediate element 12 carried by the support element 11 and
rotating with respect thereto about a first fixed axis A; [0037] a
rigid tensioner element 13, carried by the intermediate element 12
and rotating with respect thereto about a second axis B parallel to
the first axis A and distinct from it, the axis B therefore being
mobile due to the rotation movement of the intermediate element 12
with respect to the support element 11 about the axis A; [0038] a
first tensioner pulley 14 and a second tensioner pulley 15 carried
by the tensioner element 13 and rotating with respect thereto about
respective axes distinct from said first and second axis; the
tensioner pulleys 14 and 15 cooperate with the back of respective
branches 9a, 9b of the belt 9 arranged immediately upstream and
downstream of the second pulley 5 (FIG. 1); [0039] a spring 16
acting between the base element 11 and the intermediate element 12
to push the tensioning pulleys 14, 15 into contact with the belt
9.
[0040] FIGS. 2, 3 and 4 schematically illustrate three embodiments
that differ essentially due to the relative position of the axes A
and B with respect to the second pulley 5.
[0041] In particular, in the first embodiment (FIG. 2) the axis A
is positioned within the area occupied by the second pulley 5,
close to the periphery thereof, so that the axis B is close to the
axis of the second pulley 5 and moves about the same; in the second
embodiment (FIG. 3) the axis A coincides with the axis of the
second pulley 5; in the third embodiment (FIG. 4), both the axis A
and the axis B are positioned outside the area occupied by the
second pulley 5.
[0042] These variations allow different assembly solutions on the
vehicle and, in particular, adaptation of the tensioner to the
layout of the drive and to the fixing points available on the
electric machine 6 or close thereto.
[0043] Construction examples of the three embodiments briefly
described above are given below. For the sake of brevity, the
description of particular accessories is omitted, such as bushings,
bearings or other axial or radial support elements, used in order
to reduce the friction and/or wear between the parts in relative
movement, or to produce controlled damping between parts in
relative movement. Said details are illustrated, in particular in
the exploded views, and their function will be evident to a person
skilled in the art.
[0044] FIGS. 5 to 9 illustrate an embodiment example of the first
solution (diagram of FIG. 2), indicated overall by 10A, which is
described below by using the same reference numbers for the parts
already described with reference to the preceding figures.
[0045] The support element 11 of the tensioner 10A, expediently
made of pressed sheet metal, is substantially disc-shaped with a
flat bottom wall 19 and an outer perimeter edge 20 folded axially
towards the electric machine 6 (FIGS. 7 and 8). The support element
11 is further provided with a flanged outer lateral appendage 21,
provided with a plurality of fixing holes 22 adapted to allow the
fixing on the casing (not illustrated) of the electric machine 6 by
means of screws (not illustrated). Expediently, the screws are
housed passing through respective tubular spacers 23 (FIGS. 7, 9
and 10) fixed to the flange 21, for example by means of welding or
heading, and having the purpose of axially spacing the support
element 11 from the casing of the electric machine 6. The support
element 11 integrally comprises a pin 24 which axially extends from
the bottom wall 19 in an eccentric position with respect to the
edge 20 and defines the axis A.
[0046] The intermediate element 12 of the tensioner 10A is
substantially disc-shaped having an axis B with an eccentric hole
25 rotatingly engaged by the pin 24.
[0047] The tensioner element 13 comprises an annular hub portion 30
rotating about the intermediate element 12 (and therefore the axis
B) and a pair of arms 31, 32 extending radially in directions
diverging from the hub portion 30.
[0048] Expediently, the tensioner element 13 consists of a pair of
half-shells 13a, 13b (FIGS. 9, 10) made of pressed sheet metal,
which are sandwich-assembled on opposite sides of the intermediate
element 12 forming the hub portion 30 which encloses the
intermediate element 12 and the arms 31, 32 on which the pulleys
14, 15 are rotatingly mounted. The two half-shells 13a, 13b are
identical to each other for reasons of economy of scale.
[0049] One of the two tensioner pulleys (15) is preferably mounted
in an adjustable manner on the respective arm 32, so as to allow
variation of the centre distance between said pulleys to adjust the
installation tension of the belt and to compensate for the
manufacturing tolerances of the belt and drive layout.
[0050] For said purpose, the tensioner pulley 15 is mounted by
means of a bearing 34 on a sleeve 39 which is telescopically
coupled to an intermediate bushing 33 (FIG. 7) by means of a
prismatic coupling 38, for example with hexagonal section; the
bearing 34 is axially comprised between respective shoulders of the
sleeve 39 and the intermediate bushing 33.
[0051] The intermediate bushing 33 comprises a discoidal end flange
35, on the opposite side of the bearing 34, from which an eccentric
peg 36 axially extends (FIGS. 7 and 9). The peg 36 is housed in a
hole 37 of the arm 32, defining a rotation axis C of the
intermediate bushing 33 with respect to the arm 32.
[0052] The arm 32 further comprises an arcuate slot 44 having a
centre of curvature on the axis C. A screw 42, arranged passing
through the slot 44 (without transversal play) and through the
intermediate bushing 33, is screwed in the sleeve 39.
[0053] The flange 35 of the intermediate bushing 33 is lastly
provided with a prismatic, for example hexagonal, seat 45 for a
wrench (not illustrated), arranged diametrically opposite to the
peg 36 with respect to the axis of the intermediate bushing 33.
[0054] Since the two half-shells 13A, 13B are identical to each
other, also the arm 31 has the hole 37 and the slot 44, although
not necessary for the purposes of adjustment of the position of the
tensioner pulley 14. Therefore, the tensioner pulley 14 is mounted
on a support 49 engaging the slot 44 in a fixed manner.
[0055] The spring 16, acting between the support element 11 and the
intermediate element 12 so as to exert on the latter a thrust
maintaining the pulleys 14 and 15 against the belt 9, is a helical
spring with a number of coils varying between 0.5 and 3, for
example 2, housed in the support element 11 and provided with end
curls 40, 41 cooperating respectively with a seat 46 on the edge 20
of the support element 11 and a seat 47 obtained in an axial
protrusion 48 of the intermediate element 12.
[0056] Operation of the tensioner 10A, already partly evident from
the preceding description, is as follows.
[0057] At installation, the screw 42 for blocking the intermediate
bushing 33 is loosened, therefore the tensioner pulley 15 can be
arranged in the most favourable position for installation of the
belt 9. After the belt 9 has been installed on the pulleys 2, 5, 7,
with the respective branches 9a, 9b arranged with their back in
contact with the tensioner pulleys 14, 15, the tensioner pulley 15
can be moved, by means of a spanner in the seat 45 on the
intermediate bushing 33, rotating it about the axis C, to a
position such as to bring the belt 9 to the nominal tension under
the thrust of the spring 16. The screw 42 is then tightened, fixing
the intermediate bushing 33 to the tensioner element 13.
[0058] During operation, the tensioner element 13 is arranged in a
position of equilibrium upon the rotation about the axis B under
the action of the forces exchanged between the branches 9a, 9b of
the belt 9 and the respective tensioner pulleys 14, 15. The
tensioned branch of the belt 9 can be the branch 9a or the branch
9b according to the operating mode of the electric machine 6 (as
generator driven by the IC engine 4 or as motor).
[0059] When the electric machine passes from one operating mode to
the other, the tensioner element 13 rotates rigidly with respect to
the intermediate element 12 about the axis B and is arranged in a
new position of equilibrium, rotated with respect to the preceding
position towards the new tensioned branch; also the intermediate
element 12 finds a new position of equilibrium by rotating with
respect to its axis A.
[0060] Since the tensioner element 13 is rigid and there is no
elasticity interposed between the tensioner pulleys 14 and 15, the
tensioner 10 is very reactive and promptly compensates for the
instantaneous tension variations of the belt.
[0061] The length variations of the belt 9 during the working life
thereof are compensated by rotation of the intermediate element 12
with respect to the support element 11 about the axis A (in an
anticlockwise direction with reference to FIGS. 2 and 5) under the
action of the spring 16.
[0062] FIGS. 11 to 16 illustrate a construction solution of the
second embodiment of the invention according to the diagram of FIG.
3, indicated overall by 10B.
[0063] The support element 11 of the tensioner 10B, expediently
made of pressed sheet metal, integrally comprises a tubular sleeve
50 having an axis A and a plurality of appendages 51 (FIG. 11, 15,
16) extending radially from one axial end of the sleeve 50 and
provided with fixing holes 52 for fixing to the electric machine 6
by means of screws not illustrated.
[0064] The intermediate element 12 of the tensioner 10B comprises
an annular hub portion 53, which is mounted rotatingly on the
sleeve 50, and an arm portion 54 radially extending from the hub
portion 53 and bearing an axial pin 55 having an axis B (FIGS. 13,
15, 16).
[0065] The spring 16 acts between the support element 11 and the
intermediate element 12, analogously to what is described for the
tensioner 10A.
[0066] The tensioner element 13 has a substantially annular shape,
with a main portion 60 substantially C-shaped and extending for
approximately three quarters of the circumferential development of
the tensioner element 13. The tensioner pulleys 14, 15 are mounted
rotatingly on the respective ends 61, 62 of the main portion
60.
[0067] In the example illustrated the pulleys 14, 15 are mounted on
the tensioner element 13 in a fixed manner; alternatively, one of
the tensioner pulleys 14, 15 can be mounted in an adjustable manner
as described for the tensioner 10A.
[0068] The main portion 60 has a seat 63 arranged in an
intermediate position between the tensioner pulleys 14, 17, which
is rotatingly engaged by the pin 55, thus defining an articulated
connection having an axis B between the intermediate element 12 and
the tensioner element 13.
[0069] Lastly the tensioner element 13 comprises a stiffening
portion 64, less thick than the main portion 60, which integrally
connects the ends 61, 62 of the main portion 60.
[0070] Operation of the tensioner 10B is substantially analogous to
that of the tensioner 10A described.
[0071] FIGS. 17 to 22 illustrate a construction solution of the
third embodiment of the invention according to the diagram of FIG.
4, indicated overall by 10C.
[0072] The support element 11 of the tensioner 10C is substantially
C-shaped and comprises an intermediate circular bulge 65, defining
a frontal cylindrical cavity 66 having an axis A (FIGS. 19, 20),
and a plurality of holes 67 (FIGS. 17, 18) for fixing to the
electric machine 6.
[0073] The intermediate element 12 comprises a disc 68, from
opposite 1faces of which a first eccentric pin 69 having an axis A
and a second pin 70 coaxial with the disc 68, having an axis B,
extend axially in opposite directions.
[0074] The pin 69 is rotatingly coupled to the cavity 66; an axial
screw 74, passing through the support element 11, axially blocks
the intermediate element 12 on the latter.
[0075] The spring 16 is in this case a cylindrical helical spring
housed partially in respective annular frontal seats 76, 77
obtained on the bottom of the cavity 66 and in the pin 69.
[0076] The tensioner element 13 comprises an annular hub portion 78
rotating about the second pin 70 of the intermediate element 12
(and therefore about the axis B) and a pair of arms 79, 80 radially
extending in directions diverging from the hub portion 78. The arms
79, 78 are expediently integrally connected to each other by a
stiffening portion 81.
[0077] The tensioner pulleys 14, 15 are mounted rotatingly on the
ends of the arms 79, 80. Although not illustrated, one of the
tensioner pulleys 14, 15 can be mounted in an adjustable manner on
the respective arm 79, 80 as described for the tensioner 10A.
[0078] Operation of the tensioner 10C is conceptually analogous to
that of the tensioners 10A and 10B.
[0079] From an examination of the characteristics of the tensioners
described, the advantages of the present invention are evident.
[0080] The use, in combination, of an intermediate support element
12 rotating about a first axis A under the action of a spring 16
and a rigid tensioner element 13 rotating with respect to the
intermediate element 12 about a second axis B and bearing both the
tensioner pulleys that allows a high reactivity to the sudden
variations in tension of the belt to be obtained and, at the same
time, recovery of the belt elongations.
[0081] Lastly it is clear that modifications and variations that do
not depart from the protective scope defined by the claims can be
made to the tensioners described.
* * * * *